You can send a logout command via dbus to KDE, which should (if it can) terminate the session.
qdbus org.kde.ksmserver /KSMServer logout 0 0 0
dbus is a messaging system that lets applications communicate with each other, and the qdbus command is a utility for sending dbus messages to applications.
Applications register with dbus, and the ksmserver part of KDE is the session manager - it looks after who is logged in.
So we are sending a message to ksmserver to the /KSMServer interface and telling it to logout. The message we are sending is the exact same message that is sent to KSM when you click on the logout icon on your desktop.
The three zeros are parameters and can alter the type of logout we are doing:
First parameter:
0 = Do not wait for confirmation
1 = Wait for confirmation (with a 30 second timeout)
Second parameter:
-1 = Prompt for action, defaulting to shutdown (Only makes sense when waiting for confirmation.)
0 = Logout
1 = Restart
2 = Shutdown
The third parameter is the "when" parameter, but it isn't clear what its impact is.
Best Answer
The correct way to login as root is to type:
This works on systems where sudo is inavailable or not configured.
Some distributions disallow logging in as root and then one should run his commands like this: